seasonable

1. In keeping with the time or the season. See Usage Note at seasonal.
2. Occurring or performed at the proper time; timely.

adjective

Occurring at a fitting or advantageous time: auspicious, favorable, opportune, propitious, prosperous, timely, well-timed. See luck/misfortune/chance.

Definition: timely, appropriate
Antonyms: ill-timed, inappropriate, inclement, unfitting, unseasonable, unsuitable, untimely

Within a reasonable time; timely.

The term seasonable is usually used in connection with the performance of contractual obligations that must be completed "seasonably." The facts and circumstances of each case define a reasonable period of time.

The adjective has 2 meanings:

Meaning #1: in keeping with the season
  Antonym: unseasonable (meaning #1)

Meaning #2: done or happening at the appropriate or proper time
  Synonyms: timely, well-timed, well timed